Updated 23 December 2014

Are public swimming pools unhygienic?

Swimming is great for exercise and physical therapy, but if you don’t have the luxury of a pool at home you may have wondered, as this reader did: just how hygienic is that local municipal or gym "communal bath"?


"After a year of operations, due to burst appendix and hernia, my doctor suggested some gentle swimming to stretch the body.

"I joined a small club and forced myself to slowly swim in the warm water. But this past month the gym has taken in classes and classes of toddlers from nearby nursery schools, and I feel I am swimming in kids urine!

Am I being silly? Does the chlorine kill the urine? I just have not been able to get in the water as it all seems so not clean."

- Reader query from the EnviroHealth Forum

What lurks beneath the sparkling surface?

Swimming strengthens the body while the water buoys it up and protects against exercise-related injury, making it a popular and frequently recommended therapy for people recovering from an injury, operation or chronic illness.

The benefits of this are certainly likely to outweigh the potential health dangers associated with public pools.

But it’s not silly to be concerned about the risks, even if they are low - especially if you’re in a physically vulnerable state.

Just about any pool will contain pollutants, although these should be minimal if the pool is well maintained, as required by law.

Swimmers introduce various pollutants from their bodies (e.g. suncream and cosmetics) and the disinfectants used to clean the pool also add to the "chemical load".

If your immune system is compromised, as may be the case if you've been ill or recently had surgery, you are more vulnerable to infection by any micro-organisms in the water.

You may also be more vulnerable to the negative effects of disinfectant chemicals like chlorine, although most studies on this show that the health risks apply mainly to children and people who spend many hours in the pool environment, like professional swimmers.

The real nasty: human waste

Urine itself is not really a concern, although it can react with the disinfectants to produce unhealthy chemicals. Far more serious is being exposed to faecal matter in the pool, which is definitely more of a risk when swimming with small children! If anyone defecates in a pool, it should be immediately cleared of swimmers and not used until it has been properly cleaned.

Even if there isn’t direct defecation in the water, small amounts of faecal matter can actually be carried in on people’s bodies. This is why it’s often suggested that swimmers shower before swimming, to remove traces of organic pollutants and also cosmetics that would otherwise end up in the pool. If this isn’t a requirement at your club or gym, you might suggest that it become so – or at least ask if a notice can be put up suggesting it.

Stay clean and safe

- Find out when children’s swimming classes are held so that you can avoid them if possible.
- Don’t swallow the pool water, keep your eyes closed underwater, and have a shower immediately after swimming.
- Don't swim if you have any open cuts or sores.
- Don’t spend longer in the pool than you need to do your exercises.
-  If you notice any worrisome symptoms, such as rash, diarrhoea or eye irritation, then definitely stop using the pool until you’ve consulted your doctor.

- Olivia Rose-Innes, EnviroHealth Editor. @ORoseInn

Image: Child at pool edge: Shutterstock.

Olivia Rose-Innes is Health24’s EnviroHealth Editor. Read more of her columns and articles or post a question to her expert forum.


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